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Sirtuins are a family of enzymes that fulfill various important biological functions. Investigators have looked for the implication of Sirtuin genes in cell signaling mechanisms, in the formation and silencing of heterochromatin, in the regulation of ion channels, and in the modulation of the cellular redox reactions[2]. Different model organisms have been previously used to conduct these studies; among them, there are yeasts, nematodes, and fruit flies. Each one has made some valuable contribution into the vast body of knowledge related to this field.

However, gaps in the understanding of Sirtuins functions still remain to be filled. In this optic, the purpose of this experiment is to uncover the impact of oxidative stress on Tetrahymena thermophila Sirtuin, THD18. This protist offers several advantages. In addition, of being widespread, it is easy to culture and to reproduce in the laboratory environment, inexpensive to maintain, and have a short generation time. From a phylogenetic perspective, mammalian Sirtuins share some homology with those found in Tetrahymena. Therefore, results of scientific investigations conducted on Tetrahymena Sirtuins can have direct applications to other fields such as human medicine.

At a molecular level, oxidation reactions in living organisms are catalyzed by enzymes. In human beings for example, enzymes called SIRT3, and SIRT4, which are Sirtuins, participate in oxidative reactions. While SIRT3 protects against oxidative stress by acetylating and activating the Super Oxide Dismutase 2 (SOD2), which is an enzyme found in the mitochondria, SIRT4 on the other hand has the opposite effect, and tends to facilitate the oxidation of fatty acid in the liver and muscle cells. Based on this fact, we hypothesized that the level of mRNA of T. thermophila sirtuin genes will increase in response to high levels of oxidative stress.


This poster, the 1st place winner for STEM individual posters, was presented at the 29th Semi-Annual Honors and Undergraduate Research Scholars Poster Presentation at New York City College of Technology, Dec.5, 2018.

Mentor: Dr. Ralph Alcendor, Biology.